Metal-filament lamp.



.L E. C. STRVUVE. METAL FILAMENT LAMP.

APPLICATION f lLED MAR.21.1914.

Patented Mar. 26, 19m

' mmm@ (ng. L+

JOHANN EMIL CHRISTIAN STRUVE, OF HAMBURG, GERMANY.

METAL-FILAMENT LAMP.

Specification of Letters Patent.

Patented Mar. 26, 1918.

Application filed March 27, 1914. Serial No. 827,714.

To all whom t may concern: I

Be it known that I, J oHANN EMIL CHRIS- TIAN STRUVE, a subject of the German Emperor, and resident of No. 10 Spitalerstrasse, Hamburg, l, Germany, have invented certain new and useful Improvements in or Relating to Metal-Filament Lamps, of which the following is a specication.

The invention relates to a metal filament lamp in which the luminous filament is arranged in the lamp in such a manner as to represent the contour of letters or the like. As the length of the filament is determined by the voltage and the thickness of the lilament and as owing to their differentlformation the contours of letters and the like are not of equal length, in the various letters both the parts which represent the letter and also that portion of the filament which does not belong to the letter are of di`erent lengths. Consequently the luminous effect will differ in the case of different letters when only the. luminosity of the portion of the filament which forms the letter is utilized. In order to obviate this and to obtain equal luminous effects for all letters,the portion of the filament not required to form the contour of the letter is arranged in the lamp in such a manner that although not itself visible it participates in the illumination. In order to eliminate the prejudicial reflection of light arising from the luminous letter, the rear half of the lamp or casing is formed of opaque or dark colored lass.

The lamp is illustrated by way of example in the accompanying drawing, in which:

Figures l and 2 illustrate in front elevation two lamps exhibiting the letters E and J.

Figs. 3 and l are respectively a front and side elevation of the screen on the lamp at its upper part and rear half.

The supplemental metal filament n is in' terposed in the leading-in wire cof the lamp o (Fig. l) or connected therewith (Fig. 2). In the former case, the filament is relatively shorter owing to the reater length of the contour of the letter ID, while in the latter case it is longer in view of the shorter length of the contour of the letter J. The contours of the letters are formed by the filament cl which is lixed to the suitably shaped filament carrier b by means of filament supports c, the carrier b likewise supporting the upper filament n. The upper portion 0 of the lamp which surrounds the vfilament n, consists of dulled glass or the like, so that although this filament is not visible it cooperates in the illumination.

The rear half p of the lamp which forms the background of the letter, may be also rendered opaque or dark in color.

What I claim is A lamp comprising a bulb having a dulled glass section, a metal filament having a letter-formingv section located within the main portion ot the bulb and a supplementary section located within the dulled section of the bulb, and a carrier for the letter-forming section and also for the supplementary section, said supplementary section being adapted to be rendered invisible by the dulled bulb section, while transmitting light therethrough.

Signed by me at Hamburg, Germany, this 14th day of March, 1914.

JOHANN EMIL CHRISTIAN STRUVE.

Witnesses:

AUGUST WENK, ERNEST H. L. MUMMENHOFF.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. G. 

